Description:
In a valley among the foothills of the mountains, below the springs of Thalos, [Finrod] saw lights in the evening, and far off he heard the sound of song. ... as he drew near he perceived that it was not [Orcs]; for the singers used a tongue that he had not heard before, neither that of Dwarves nor of Orcs. Then Felagund ... looked down into the camp, and there he beheld a strange people.

Now these were a part of the kindred and following of Bëor the Old, as he was afterwards called, a chieftain among Men. After many lives of wandering out of the East he had led them at last over the Blue Mountains, the first of the race of Men to enter Beleriand; and they sang because they were glad, and believed that they had escaped from all perils and had come at last to a land without fear.

The Silmarillion, Quenta Silmarillion, Ch 17, Of the Coming of Men into the West

It was not long therefore before Felagund could hold converse with Bëor; and while he dwelt with him they spoke much together. But when he questioned him concerning the arising of Men and their journeys, Bëor would say little; and indeed he knew little, for the fathers of his people had told few tales of their past and a silence had fallen upon their memory. 'A darkness lies behind us,' Bëor said; 'and we have turned our backs upon it, and we do not desire to return thither even in thought. Westwards our hearts have been turned, and we believe that there we shall find Light.'

The Silmarillion, Quenta Silmarillion, Ch 17, Of the Coming of Men into the West

Soon after the departure of Felagund the other Men of whom Bëor had spoken came also into Beleriand. First came the Haladin; but meeting the unfriendship of the Green-elves they turned north and dwelt in Thargelion.... In the next year Marach led his people over the mountains; they were a tall and warlike folk, marching in ordered companies, and the Elves of Ossiriand hid themselves and did not waylay them. But Marach, hearing that the people of Bëor were dwelling in a green and fertile land, came down the Dwarf-road, and settled in the country south; and east of the dwellings of Baran son of Bëor; and there was great friendship between those peoples.

Felagund himself often returned to visit Men; and many other Elves out of the west-lands, both Noldor and Sindar, journeyed to Estolad, being eager to see the Edain, whose coming had long been foretold. Now Atani, the Second People, was the name given to Men in Valinor in the lore that told of their coming; but in the speech of Beleriand that name became Edain, and it was there used only of the three kindreds of the Elf-friends.

The Silmarillion, Quenta Silmarillion, Ch 17, Of the Coming of Men into the West